The presence of pathogenic organisms in biological fluids and tissue is of continuous concern, as is the potential for transfer of such organisms to and from the surfaces of medical articles. This transfer can be particularly problematic in hospitals or other care facilities, as certain medical articles may be exposed to multiple individuals or remain in situ for long periods without adequate cleaning. Even if certain medical personnel hygiene protocols are rigorously followed, the exposed surfaces of these devices may still attract pathogenic organisms by virtue of a continuous or semi-continuous proximity to pathogen bearing individuals or substrates. For at least these reasons, methods for minimizing the transmission of pathogens from medical article surfaces to human tissue are of significant importance.
Attempts have been made to provide medical article surfaces that are inherently antimicrobial, either by composition or use of antimicrobial drug delivery systems. These surfaces can be insufficiently effective in reducing transfer for at least four potential reasons: 1) when used as a delivery system, antimicrobial or active agents may be exhausted well before the end of the service lifetime of the medical article; 2) the surface antimicrobial properties are eventually impaired as dead cells, high organic load, and other adsorbed debris mask the antimicrobial properties of that surface; 3) antimicrobial agents in the material or in an external coating fail to elute sufficiently; 4) the antimicrobial agent is unsafe for human tissue contact; and 5) antimicrobial kill may take too long to develop.
Polyhaloolefins, including polyvinyl chloride polymers, have proven particularly useful in constructing many medical articles, including stethoscopes. Attempts have been made to imbue polyhaloolefin plastisols with antimicrobial or biocidal agents. The antimicrobial agent, such as triclosan, is typically mixed with the polymeric resin prior to forming said medical article in an attempt to impart controlled release of the antimicrobial agent.